Most conventional methods to update a computer system of the user are a method of installing software from a recording medium such as a CD-ROM. The computer system of the user is referred to hereafter simply as a user system.
In recent years, however, there is adopted a method of downloading software from a vendor computer system providing software by way of a network and installing the downloaded software in a user system. The vendor computer system is referred to hereafter simply as a vendor system.
In accordance with this method of installing software in a user system through a network, typically, in the user-system information on the configuration of software used in the user system is generated, and the user system periodically receives information on software updates from a patch management server of the vendor system byway of the network. Then, the user system compares the generated information on the configuration of software used in the user system with the received information on software updates in order to examine the configuration for pieces of software that need to be updated. The user system then displays a list extracted from a result of the examination as a list of pieces of software to be updated. The user can select a piece of software from the displayed list and request the vendor system to update the selected piece of software. At such a request, the vendor system transmits an software-updating patch for the selected piece of software to the user system by way of the network. Then, the user system applies the software-updating patch to the selected piece of software in order to update the software. The patch herein is a difference file used for correcting a program of the software to be updated.
For example, Japanese Patent Laid-open No. 2002-55839 discloses a typical method whereby a patch database is constructed on the server side and a client receives patch information by way of a network from the server side and applies the patch to a computer system of the client.
In addition, there is also a method of updating software without degrading the availability of the software or the user system. In accordance with this method, in order to update a user system of a critical mission, a person in charge of system management on the vendor side takes a software-updating patch to the user system, applying the patch to a piece of software to be updated while the user system is operating. By updating the piece of software without restarting the user system and the software, the availability of the user system and the software can be prevented from deteriorating.
Furthermore, there is also a method, by which a vendor constructing a user system prepares a system identical with the user system on the vendor side so that an updated user system can be tested on the vendor side.
A technique to update software of a user system through a network is easy to implement in comparison with a technique to update software of a user system by using a recording medium. In addition, the technique to update software of a user system through a network has a merit of allowing most recent software to be used.
By adoption of the conventional technique to update software of a user system through a network, however, it is quite within the bounds of possibility that there is raised a problem of a lower availability following the operation to update the software. The lower availability is caused by a failure occurring in the user system, the operation of which was changed by the operation to update the software. The failure occurring in the user system causes the user system to be halted or restarted, in turn giving rise to the lower availability. As a result of the operation to update the software, it is also quite within the bounds of possibility that there are raised a problem of an inability to reach a service level requested of the user system and a problem that the user can no longer carry out a desired function because of the operation to update the software.
In particular, when it is desired to update a piece of software due to a serious reason such as a detected fragility in security or a found bug, it is quite within the bounds of possibility that the problems described above cause a big damage. In addition, in the case of a system that must operate 365 days a year and 24 hours a day, the software of the system has to be updateable with a high degree of reliability.
Further, it is quite within the bounds of possibility that a peculiar software patch made by the vendor does not necessarily operate correctly for the configuration of a user system. In particular, in the case of a user system executing software of an open source or the like, it is quite within the bounds of possibility that the user itself changes the source code of the software. It is therefore quite within the bounds of possibility that the user system has a configuration unique to the user. As a result, in many cases, a peculiar software patch created by the vendor is not applicable to the user system.
It is thus an object of the present invention addressing the problems described above to provide a system-updating method for updating software of a user system through a network as a method, which allows work to update the software to be carried out in the user system with ease and is capable of assuring the high reliability and service level of the user system after the software is updated.